In general, a chain or belt transmission device for valve timing in an internal combustion engine, or for transmitting rotational power in another drive mechanism, includes a chain, a belt, or other flexible power transmission medium. In the valve timing transmission, as shown in FIG. 7, a chain CH transmits power from a driving sprocket S1, or pulley, to one or more driven sprockets S2, or pulleys, The transmission typically includes a pivotally mounted, movable, sliding contact guide Ga, which cooperates with a tensioner T to maintain appropriate tension in the chain CH, and a fixed sliding contact guide Gb, which prevents widthwise vibration and widthwise movement of the chain or belt, causing it to run off the guides. The movable guide and the fixed guide are attached to a frame of the engine or other drive mechanism by suitable pins P, or by bolts or similar mountings.
FIG. 4 is an exploded elevational view of a plastic movable guide 300, designed to be used as tensioner lever in a chain transmission, and described in the specification of Japanese Patent Application No. 2000-382798. FIG. 5 is a plan view from the bottom side of FIG. 4, and FIG. 6 is a cross-sectional view taken on plane VI—VI in FIG. 4.
Guide 300 comprises a guide body 310, which including a shoe 310a, on the surface of which a transmission medium such as a traveling chain CH, a belt, or the like, is brought into sliding contact, and a plate-receiving portion 310b, provided on the back of the shoe 310a and extending along the longitudinal direction of the guide. The shoe and the plate-receiving portion are integrally molded as a unit from a synthetic resin. A reinforcing plate 320, composed of a rigid material, is fitted into a slot 310c in the plate-receiving portion of the guide body, for reinforcing the guide body. The opening of this slot faces away from the shoe, and the slot extends along the longitudinal direction of the guide, Adjacent one end of the plate-receiving portion 310b a mounting hole 310d is provided, for mounting the guide body on the frame of an engine or other machine. A mounting hole 320a is provided in the reinforcing plate 320 adjacent one end thereof, at a location such that, when the reinforcing plate is properly positioned in the slot of the guide body, the holes 310d and 320a are in register with each other so that they can receive a pivot means such as a mounting bolt or the like and be held together by the pivot means as well as pivoted thereon. The plate-receiving portion 310b also includes ribs 310f for enhancing the strength of the guide body 310.
As shown in FIG. 6, a locking piece 310e, formed on the guide body 310, is engageable with a locking hole 320b in the reinforcing plate 320, to prevent the reinforcing plate from being dislodged from the slot 310c. 
Since the shoe 310a and the plate-receiving portion 310b are integrally molded as a unit from synthetic resin, the transmission medium slides on the guide body 310 itself, and it is not necessary to provide a separate shoe. Consequently, the number of the parts and the number of production steps are reduced. The reinforcing plate 320, fitted into the slot 310c, increases the strength of the guide in the pivoting direction. As a result the bending rigidity, toughness, and strength of the guide are significantly improved. Sliding plastic guides of this kind satisfy the recent demand for low cost and high reliability, and have come into widespread use.
Because the guide body bulges and shrinks with the changes in temperature encountered in an engine, these guides require a play or a gap G between the locking piece 310e and the locking hole 320b, as seen in FIG. 6. Because of this gap, vibration during engine operation causes reinforcing plate to move in the slot 310c, and the reinforcing plate and guide body collide with each other to generate noise. The surface of the slot also becomes worn. Thus, there has been a demand for further improvements in plate-reinforced plastic movable guides.
Accordingly, objects of the invention are to solve the above-mentioned problems encountered in the use of conventional sliding contact guides, to provide a sliding contact guide in which the reinforcing plate and the guide body are reliably secured together so that movement of the reinforcing plate in the slot of the guide body, does not generate noise due to vibration, and to reduce wear and thereby increase the useful life of the guide.